This invention relates to open systems printing.
Printing is often a proprietary sub-system of computer operating systems. This is especially true for production or high-speed printing (i.e., greater than 100 pages per minute). For example, IBM™ MVS™ mainframes 10, 12 (FIG. 1) are connected to IBM™ printers 14, 16 over IBM™ bus-and-tag channels 18, 20, Microsoft™ NT™ server 22 is connected to NT™ printer 24 over proprietary bus 26, and image server 28 is connected to image printers 30 over proprietary busses 32. In a typical MVS™ environment, print files are generated from a mainframe MVS™ application and sent to a Job Entry Sub-System (JES). The print job is routed over the proprietary bus to a printer directly connected to the proprietary bus. The job is then printed using JES commands.
When new processors are developed and installed, new printers corresponding to the new technology are also installed. Dedicated, high-bandwidth channel bus extenders are used to connect remote high-speed printers to a central mainframe location.
Client/server systems typically include smaller desktop computers (clients) connected to larger more powerful computers (servers). To print a client/server print stream on a high-speed printer, the print stream is typically routed (arrow 34) to a mainframe, e.g., MVS™ 10, and then routed to a high-speed printer, e.g., printers 14. The mainframe is effectively made a high-cost print server for the distributed client/server system.
Switch 36 enables either MVS™ 12 or a VAX™ mainframe 38 to send print streams to printer 40. If MVS™ 12 is configured to send print streams through switch 36 and a user instead wants to send print streams from VAX™ 38 to the printer, the user enables the VAX™ and disables the MVS™ and configures the switch accordingly. Approximately 20 minutes to an hour is required to re-configure the mainframes and switch. A new switch is needed to allow a different hardware platform, e.g., NT™ server 22, to share a printer with MVS™ 12 and/or VAX™ 38.